Generally, the clamp type lamp holder is comprised of a lamp stem constructed of snake tubing that is positioned through random turning. Some defects exist and are as follows.
Because the snake tube is able to bend at a large arc, the adjustable range has limitations. Because of the limited length (max. 20 cm) of the snake tube that is applied to the clamp type lamp holder, the desired angle is difficult to adjust.
Because ring joints support the snake tubing, and are connected together, the joint could possibly become loose due to usage and/or aging. This limits the life span due to the decrease of the support force.
Because of limited support for the snake tube as mentioned above, the lamp head can only support the use of a lightweight common bulb and shell rather than heavier and better lamp heads (such as the halogen lamp).
For outdoor clamp type lamp holders (such as garden lamps), the lamp head is usually vertically adjustable but, because it is difficult to get the appropriate position for clamping, ideal illumination is not always attainable.